Purposeful gazing and vergence control for active vision

Abstract

The purposeful-gazing capability of active vision offers advantages to many manufacturing tasks. This paper discusses the problems associated with purposeful gazing and fixation of attention for active vision. In binocular active vision, gazing at a selected target refers to directing the visual axes to capture the target in the (appropriate part of) the visual field by both sensors (cameras), and holding gaze refers to directing the visual axes of the sensors so as to maintain the target or point of interest in the visual field of both sensors. This paper proposes solutions to the important problems involved in gaze stabilization by developing techniques for vergence error extraction, and vergence servo control. Vergence is the tilt movement process of two visual sensors (in a binocular system) in opposite directions to fixate at a selected point. Binocular gazing is realized by decreasing the disparity which represents the vergence error. In order to obtain the disparity for extraction of vergence error, a phase-based approach that robustly and efficiently estimates vergence disparity is developed. To control vergence, we present a dual sampling-rate approach for vision-sensor-based dynamic servo control.